drivers/misc/cxl/file.c

   1 /*
   2  * Copyright 2014 IBM Corp.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version
   7  * 2 of the License, or (at your option) any later version.
   8  */
   9
  10 #include <linux/spinlock.h>
  11 #include <linux/module.h>
  12 #include <linux/export.h>
  13 #include <linux/kernel.h>
  14 #include <linux/bitmap.h>
  15 #include <linux/sched.h>
  16 #include <linux/poll.h>
  17 #include <linux/pid.h>
  18 #include <linux/fs.h>
  19 #include <linux/mm.h>
  20 #include <linux/slab.h>
  21 #include <asm/cputable.h>
  22 #include <asm/current.h>
  23 #include <asm/copro.h>
  24
  25 #include "cxl.h"
  26 #include "trace.h"
  27
  28 #define CXL_NUM_MINORS 256 /* Total to reserve */
  29 #define CXL_DEV_MINORS 13   /* 1 control + 4 AFUs * 3 (dedicated/master/shared) */
  30
  31 #define CXL_CARD_MINOR(adapter) (adapter->adapter_num * CXL_DEV_MINORS)
  32 #define CXL_AFU_MINOR_D(afu) (CXL_CARD_MINOR(afu->adapter) + 1 + (3 * afu->slice))
  33 #define CXL_AFU_MINOR_M(afu) (CXL_AFU_MINOR_D(afu) + 1)
  34 #define CXL_AFU_MINOR_S(afu) (CXL_AFU_MINOR_D(afu) + 2)
  35 #define CXL_AFU_MKDEV_D(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_D(afu))
  36 #define CXL_AFU_MKDEV_M(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_M(afu))
  37 #define CXL_AFU_MKDEV_S(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_S(afu))
  38
  39 #define CXL_DEVT_ADAPTER(dev) (MINOR(dev) / CXL_DEV_MINORS)
  40 #define CXL_DEVT_AFU(dev) ((MINOR(dev) % CXL_DEV_MINORS - 1) / 3)
  41
  42 #define CXL_DEVT_IS_CARD(dev) (MINOR(dev) % CXL_DEV_MINORS == 0)
  43
  44 static dev_t cxl_dev;
  45
  46 static struct class *cxl_class;
  47
  48 static int __afu_open(struct inode *inode, struct file *file, bool master)
  49 {
  50         struct cxl *adapter;
  51         struct cxl_afu *afu;
  52         struct cxl_context *ctx;
  53         int adapter_num = CXL_DEVT_ADAPTER(inode->i_rdev);
  54         int slice = CXL_DEVT_AFU(inode->i_rdev);
  55         int rc = -ENODEV;
  56
  57         pr_devel("afu_open afu%i.%i\n", slice, adapter_num);
  58
  59         if (!(adapter = get_cxl_adapter(adapter_num)))
  60                 return -ENODEV;
  61
  62         if (slice > adapter->slices)
  63                 goto err_put_adapter;
  64
  65         spin_lock(&adapter->afu_list_lock);
  66         if (!(afu = adapter->afu[slice])) {
  67                 spin_unlock(&adapter->afu_list_lock);
  68                 goto err_put_adapter;
  69         }
  70         get_device(&afu->dev);
  71         spin_unlock(&adapter->afu_list_lock);
  72
  73         if (!afu->current_mode)
  74                 goto err_put_afu;
  75
  76         if (!(ctx = cxl_context_alloc())) {
  77                 rc = -ENOMEM;
  78                 goto err_put_afu;
  79         }
  80
  81         if ((rc = cxl_context_init(ctx, afu, master, inode->i_mapping)))
  82                 goto err_put_afu;
  83
  84         pr_devel("afu_open pe: %i\n", ctx->pe);
  85         file->private_data = ctx;
  86         cxl_ctx_get();
  87
  88         /* Our ref on the AFU will now hold the adapter */
  89         put_device(&adapter->dev);
  90
  91         return 0;
  92
  93 err_put_afu:
  94         put_device(&afu->dev);
  95 err_put_adapter:
  96         put_device(&adapter->dev);
  97         return rc;
  98 }
  99 static int afu_open(struct inode *inode, struct file *file)
 100 {
 101         return __afu_open(inode, file, false);
 102 }
 103
 104 static int afu_master_open(struct inode *inode, struct file *file)
 105 {
 106         return __afu_open(inode, file, true);
 107 }
 108
 109 static int afu_release(struct inode *inode, struct file *file)
 110 {
 111         struct cxl_context *ctx = file->private_data;
 112
 113         pr_devel("%s: closing cxl file descriptor. pe: %i\n",
 114                  __func__, ctx->pe);
 115         cxl_context_detach(ctx);
 116
 117         mutex_lock(&ctx->mapping_lock);
 118         ctx->mapping = NULL;
 119         mutex_unlock(&ctx->mapping_lock);
 120
 121         put_device(&ctx->afu->dev);
 122
 123         /*
 124          * At this this point all bottom halfs have finished and we should be
 125          * getting no more IRQs from the hardware for this context.  Once it's
 126          * removed from the IDR (and RCU synchronised) it's safe to free the
 127          * sstp and context.
 128          */
 129         cxl_context_free(ctx);
 130
 131         cxl_ctx_put();
 132         return 0;
 133 }
 134
 135 static long afu_ioctl_start_work(struct cxl_context *ctx,
 136                                  struct cxl_ioctl_start_work __user *uwork)
 137 {
 138         struct cxl_ioctl_start_work work;
 139         u64 amr = 0;
 140         int rc;
 141
 142         pr_devel("%s: pe: %i\n", __func__, ctx->pe);
 143
 144         /* Do this outside the status_mutex to avoid a circular dependency with
 145          * the locking in cxl_mmap_fault() */
 146         if (copy_from_user(&work, uwork,
 147                            sizeof(struct cxl_ioctl_start_work))) {
 148                 rc = -EFAULT;
 149                 goto out;
 150         }
 151
 152         mutex_lock(&ctx->status_mutex);
 153         if (ctx->status != OPENED) {
 154                 rc = -EIO;
 155                 goto out;
 156         }
 157
 158         /*
 159          * if any of the reserved fields are set or any of the unused
 160          * flags are set it's invalid
 161          */
 162         if (work.reserved1 || work.reserved2 || work.reserved3 ||
 163             work.reserved4 || work.reserved5 || work.reserved6 ||
 164             (work.flags & ~CXL_START_WORK_ALL)) {
 165                 rc = -EINVAL;
 166                 goto out;
 167         }
 168
 169         if (!(work.flags & CXL_START_WORK_NUM_IRQS))
 170                 work.num_interrupts = ctx->afu->pp_irqs;
 171         else if ((work.num_interrupts < ctx->afu->pp_irqs) ||
 172                  (work.num_interrupts > ctx->afu->irqs_max)) {
 173                 rc =  -EINVAL;
 174                 goto out;
 175         }
 176         if ((rc = afu_register_irqs(ctx, work.num_interrupts)))
 177                 goto out;
 178
 179         if (work.flags & CXL_START_WORK_AMR)
 180                 amr = work.amr & mfspr(SPRN_UAMOR);
 181
 182         /*
 183          * We grab the PID here and not in the file open to allow for the case
 184          * where a process (master, some daemon, etc) has opened the chardev on
 185          * behalf of another process, so the AFU's mm gets bound to the process
 186          * that performs this ioctl and not the process that opened the file.
 187          */
 188         ctx->pid = get_pid(get_task_pid(current, PIDTYPE_PID));
 189
 190         trace_cxl_attach(ctx, work.work_element_descriptor, work.num_interrupts, amr);
 191
 192         if ((rc = cxl_attach_process(ctx, false, work.work_element_descriptor,
 193                                      amr))) {
 194                 afu_release_irqs(ctx);
 195                 goto out;
 196         }
 197
 198         ctx->status = STARTED;
 199         rc = 0;
 200 out:
 201         mutex_unlock(&ctx->status_mutex);
 202         return rc;
 203 }
 204 static long afu_ioctl_process_element(struct cxl_context *ctx,
 205                                       int __user *upe)
 206 {
 207         pr_devel("%s: pe: %i\n", __func__, ctx->pe);
 208
 209         if (copy_to_user(upe, &ctx->pe, sizeof(__u32)))
 210                 return -EFAULT;
 211
 212         return 0;
 213 }
 214
 215 static long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 216 {
 217         struct cxl_context *ctx = file->private_data;
 218
 219         if (ctx->status == CLOSED)
 220                 return -EIO;
 221
 222         pr_devel("afu_ioctl\n");
 223         switch (cmd) {
 224         case CXL_IOCTL_START_WORK:
 225                 return afu_ioctl_start_work(ctx, (struct cxl_ioctl_start_work __user *)arg);
 226         case CXL_IOCTL_GET_PROCESS_ELEMENT:
 227                 return afu_ioctl_process_element(ctx, (__u32 __user *)arg);
 228         }
 229         return -EINVAL;
 230 }
 231
 232 static long afu_compat_ioctl(struct file *file, unsigned int cmd,
 233                              unsigned long arg)
 234 {
 235         return afu_ioctl(file, cmd, arg);
 236 }
 237
 238 static int afu_mmap(struct file *file, struct vm_area_struct *vm)
 239 {
 240         struct cxl_context *ctx = file->private_data;
 241
 242         /* AFU must be started before we can MMIO */
 243         if (ctx->status != STARTED)
 244                 return -EIO;
 245
 246         return cxl_context_iomap(ctx, vm);
 247 }
 248
 249 static unsigned int afu_poll(struct file *file, struct poll_table_struct *poll)
 250 {
 251         struct cxl_context *ctx = file->private_data;
 252         int mask = 0;
 253         unsigned long flags;
 254
 255
 256         poll_wait(file, &ctx->wq, poll);
 257
 258         pr_devel("afu_poll wait done pe: %i\n", ctx->pe);
 259
 260         spin_lock_irqsave(&ctx->lock, flags);
 261         if (ctx->pending_irq || ctx->pending_fault ||
 262             ctx->pending_afu_err)
 263                 mask |= POLLIN | POLLRDNORM;
 264         else if (ctx->status == CLOSED)
 265                 /* Only error on closed when there are no futher events pending
 266                  */
 267                 mask |= POLLERR;
 268         spin_unlock_irqrestore(&ctx->lock, flags);
 269
 270         pr_devel("afu_poll pe: %i returning %#x\n", ctx->pe, mask);
 271
 272         return mask;
 273 }
 274
 275 static inline int ctx_event_pending(struct cxl_context *ctx)
 276 {
 277         return (ctx->pending_irq || ctx->pending_fault ||
 278             ctx->pending_afu_err || (ctx->status == CLOSED));
 279 }
 280
 281 static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
 282                         loff_t *off)
 283 {
 284         struct cxl_context *ctx = file->private_data;
 285         struct cxl_event event;
 286         unsigned long flags;
 287         int rc;
 288         DEFINE_WAIT(wait);
 289
 290         if (count < CXL_READ_MIN_SIZE)
 291                 return -EINVAL;
 292
 293         spin_lock_irqsave(&ctx->lock, flags);
 294
 295         for (;;) {
 296                 prepare_to_wait(&ctx->wq, &wait, TASK_INTERRUPTIBLE);
 297                 if (ctx_event_pending(ctx))
 298                         break;
 299
 300                 if (file->f_flags & O_NONBLOCK) {
 301                         rc = -EAGAIN;
 302                         goto out;
 303                 }
 304
 305                 if (signal_pending(current)) {
 306                         rc = -ERESTARTSYS;
 307                         goto out;
 308                 }
 309
 310                 spin_unlock_irqrestore(&ctx->lock, flags);
 311                 pr_devel("afu_read going to sleep...\n");
 312                 schedule();
 313                 pr_devel("afu_read woken up\n");
 314                 spin_lock_irqsave(&ctx->lock, flags);
 315         }
 316
 317         finish_wait(&ctx->wq, &wait);
 318
 319         memset(&event, 0, sizeof(event));
 320         event.header.process_element = ctx->pe;
 321         event.header.size = sizeof(struct cxl_event_header);
 322         if (ctx->pending_irq) {
 323                 pr_devel("afu_read delivering AFU interrupt\n");
 324                 event.header.size += sizeof(struct cxl_event_afu_interrupt);
 325                 event.header.type = CXL_EVENT_AFU_INTERRUPT;
 326                 event.irq.irq = find_first_bit(ctx->irq_bitmap, ctx->irq_count) + 1;
 327                 clear_bit(event.irq.irq - 1, ctx->irq_bitmap);
 328                 if (bitmap_empty(ctx->irq_bitmap, ctx->irq_count))
 329                         ctx->pending_irq = false;
 330         } else if (ctx->pending_fault) {
 331                 pr_devel("afu_read delivering data storage fault\n");
 332                 event.header.size += sizeof(struct cxl_event_data_storage);
 333                 event.header.type = CXL_EVENT_DATA_STORAGE;
 334                 event.fault.addr = ctx->fault_addr;
 335                 event.fault.dsisr = ctx->fault_dsisr;
 336                 ctx->pending_fault = false;
 337         } else if (ctx->pending_afu_err) {
 338                 pr_devel("afu_read delivering afu error\n");
 339                 event.header.size += sizeof(struct cxl_event_afu_error);
 340                 event.header.type = CXL_EVENT_AFU_ERROR;
 341                 event.afu_error.error = ctx->afu_err;
 342                 ctx->pending_afu_err = false;
 343         } else if (ctx->status == CLOSED) {
 344                 pr_devel("afu_read fatal error\n");
 345                 spin_unlock_irqrestore(&ctx->lock, flags);
 346                 return -EIO;
 347         } else
 348                 WARN(1, "afu_read must be buggy\n");
 349
 350         spin_unlock_irqrestore(&ctx->lock, flags);
 351
 352         if (copy_to_user(buf, &event, event.header.size))
 353                 return -EFAULT;
 354         return event.header.size;
 355
 356 out:
 357         finish_wait(&ctx->wq, &wait);
 358         spin_unlock_irqrestore(&ctx->lock, flags);
 359         return rc;
 360 }
 361
 362 static const struct file_operations afu_fops = {
 363         .owner          = THIS_MODULE,
 364         .open           = afu_open,
 365         .poll           = afu_poll,
 366         .read           = afu_read,
 367         .release        = afu_release,
 368         .unlocked_ioctl = afu_ioctl,
 369         .compat_ioctl   = afu_compat_ioctl,
 370         .mmap           = afu_mmap,
 371 };
 372
 373 static const struct file_operations afu_master_fops = {
 374         .owner          = THIS_MODULE,
 375         .open           = afu_master_open,
 376         .poll           = afu_poll,
 377         .read           = afu_read,
 378         .release        = afu_release,
 379         .unlocked_ioctl = afu_ioctl,
 380         .compat_ioctl   = afu_compat_ioctl,
 381         .mmap           = afu_mmap,
 382 };
 383
 384
 385 static char *cxl_devnode(struct device *dev, umode_t *mode)
 386 {
 387         if (CXL_DEVT_IS_CARD(dev->devt)) {
 388                 /*
 389                  * These minor numbers will eventually be used to program the
 390                  * PSL and AFUs once we have dynamic reprogramming support
 391                  */
 392                 return NULL;
 393         }
 394         return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
 395 }
 396
 397 extern struct class *cxl_class;
 398
 399 static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
 400                            struct device **chardev, char *postfix, char *desc,
 401                            const struct file_operations *fops)
 402 {
 403         struct device *dev;
 404         int rc;
 405
 406         cdev_init(cdev, fops);
 407         if ((rc = cdev_add(cdev, devt, 1))) {
 408                 dev_err(&afu->dev, "Unable to add %s chardev: %i\n", desc, rc);
 409                 return rc;
 410         }
 411
 412         dev = device_create(cxl_class, &afu->dev, devt, afu,
 413                         "afu%i.%i%s", afu->adapter->adapter_num, afu->slice, postfix);
 414         if (IS_ERR(dev)) {
 415                 dev_err(&afu->dev, "Unable to create %s chardev in sysfs: %i\n", desc, rc);
 416                 rc = PTR_ERR(dev);
 417                 goto err;
 418         }
 419
 420         *chardev = dev;
 421
 422         return 0;
 423 err:
 424         cdev_del(cdev);
 425         return rc;
 426 }
 427
 428 int cxl_chardev_d_afu_add(struct cxl_afu *afu)
 429 {
 430         return cxl_add_chardev(afu, CXL_AFU_MKDEV_D(afu), &afu->afu_cdev_d,
 431                                &afu->chardev_d, "d", "dedicated",
 432                                &afu_master_fops); /* Uses master fops */
 433 }
 434
 435 int cxl_chardev_m_afu_add(struct cxl_afu *afu)
 436 {
 437         return cxl_add_chardev(afu, CXL_AFU_MKDEV_M(afu), &afu->afu_cdev_m,
 438                                &afu->chardev_m, "m", "master",
 439                                &afu_master_fops);
 440 }
 441
 442 int cxl_chardev_s_afu_add(struct cxl_afu *afu)
 443 {
 444         return cxl_add_chardev(afu, CXL_AFU_MKDEV_S(afu), &afu->afu_cdev_s,
 445                                &afu->chardev_s, "s", "shared",
 446                                &afu_fops);
 447 }
 448
 449 void cxl_chardev_afu_remove(struct cxl_afu *afu)
 450 {
 451         if (afu->chardev_d) {
 452                 cdev_del(&afu->afu_cdev_d);
 453                 device_unregister(afu->chardev_d);
 454                 afu->chardev_d = NULL;
 455         }
 456         if (afu->chardev_m) {
 457                 cdev_del(&afu->afu_cdev_m);
 458                 device_unregister(afu->chardev_m);
 459                 afu->chardev_m = NULL;
 460         }
 461         if (afu->chardev_s) {
 462                 cdev_del(&afu->afu_cdev_s);
 463                 device_unregister(afu->chardev_s);
 464                 afu->chardev_s = NULL;
 465         }
 466 }
 467
 468 int cxl_register_afu(struct cxl_afu *afu)
 469 {
 470         afu->dev.class = cxl_class;
 471
 472         return device_register(&afu->dev);
 473 }
 474
 475 int cxl_register_adapter(struct cxl *adapter)
 476 {
 477         adapter->dev.class = cxl_class;
 478
 479         /*
 480          * Future: When we support dynamically reprogramming the PSL & AFU we
 481          * will expose the interface to do that via a chardev:
 482          * adapter->dev.devt = CXL_CARD_MKDEV(adapter);
 483          */
 484
 485         return device_register(&adapter->dev);
 486 }
 487
 488 int __init cxl_file_init(void)
 489 {
 490         int rc;
 491
 492         /*
 493          * If these change we really need to update API.  Either change some
 494          * flags or update API version number CXL_API_VERSION.
 495          */
 496         BUILD_BUG_ON(CXL_API_VERSION != 1);
 497         BUILD_BUG_ON(sizeof(struct cxl_ioctl_start_work) != 64);
 498         BUILD_BUG_ON(sizeof(struct cxl_event_header) != 8);
 499         BUILD_BUG_ON(sizeof(struct cxl_event_afu_interrupt) != 8);
 500         BUILD_BUG_ON(sizeof(struct cxl_event_data_storage) != 32);
 501         BUILD_BUG_ON(sizeof(struct cxl_event_afu_error) != 16);
 502
 503         if ((rc = alloc_chrdev_region(&cxl_dev, 0, CXL_NUM_MINORS, "cxl"))) {
 504                 pr_err("Unable to allocate CXL major number: %i\n", rc);
 505                 return rc;
 506         }
 507
 508         pr_devel("CXL device allocated, MAJOR %i\n", MAJOR(cxl_dev));
 509
 510         cxl_class = class_create(THIS_MODULE, "cxl");
 511         if (IS_ERR(cxl_class)) {
 512                 pr_err("Unable to create CXL class\n");
 513                 rc = PTR_ERR(cxl_class);
 514                 goto err;
 515         }
 516         cxl_class->devnode = cxl_devnode;
 517
 518         return 0;
 519
 520 err:
 521         unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
 522         return rc;
 523 }
 524
 525 void cxl_file_exit(void)
 526 {
 527         unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
 528         class_destroy(cxl_class);
 529 }